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This paper introduces two classes of variational problems, determining optimal shapes for tree roots and branches. Given a measure μ , describing the distribution of leaves, we introduce a sunlight functional 𝒮 (μ) computing the total amount of light captured by the leaves. On the other hand, given a measure μ describing the distribution of root hair cells, we consider a harvest functional ℋ (μ) computing the total amount of water and nutrients gathered by the roots. In both cases, we seek to maximize these functionals subject to a ramified transportation cost, for transporting nutrients from the roots to the trunk and from the trunk to the leaves. The main results establish various properties of these functionals, and the existence of optimal distributions. In particular, we prove the upper semicontinuity of 𝒮 and ℋ , together with a priori estimates on the support of optimal distributions. [ABSTRACT FROM AUTHOR]

Background. Epiphytic bryophyte communities in the Amazon forest show a vertical gradient in species composition along the trunk of the host trees. The investigation of species traits related to this pattern has focused on the physiology of selected taxa with a clear preference for one of the extremes of the gradient. Although some species are indeed only found on the tree base or in the outer canopy, the vertical gradient is composed mainly by the variation in the abundances of species with a broader occurrence along the height zones. Therefore, this study approaches the differences among community assemblages, rather than among species, to test the role of morphological and dispersal traits on the establishment of the vertical gradient in species composition. Methods. A character state matrix was built for 104 species of the family Lejeuneaceae recorded as epiphytes in the Amazonian terra firme forests, and six binary traits supposed to influence species occurrence: dark pigmentation on leaves; ability to convolute leaves when drying; possession of thickened cell walls; reproduction mode (monoicous or dioicous); occurrence of asexual reproduction; and facultative epiphyllous habit. Based on a previous dataset on community composition along the vertical gradient, trait occurrences in random draws of the metacommunity was compared to trait occurrences in field data, in order to detect significant deviations in the different height zones. Results. Four out of the six traits tested showed significantly higher or lower occurrence in the species composition of canopy and/or understory communities. Traits related to high dispersal ability did not vary much along the vertical gradient; although facultative epiphylls were overrepresented on tree base. Dark pigmentation and convolute leaves were significantly more frequent in the canopy communities, but also significantly less frequent in communities at the base of the tree. Discussion. Dark pigmentation and convolute leaves seem to be advantageous for the establishment in the canopy zones. They may, respectively, prevent light damage and allow longer periods of photosynthesis. Interestingly, these traits occur randomly along the trunk, but are wiped out of communities on the tree base. In the relatively deep shade of the first meters of the understory, they possibly hamper net carbon gain, the first by darkening the leaf surface and the second by delaying desiccation-which can be damaging under high temperatures and low light. The fact that production of asexual propagules is not overrepresented in the most dynamic microenvironment along the gradient, the canopy, challenges current views of bryophyte life strategy theory. [ABSTRACT FROM AUTHOR]

In order to understand the coordination of leaf phenology and functional xylem anatomy, the timing of vessel wall lignification in twigs and stems in relation to leaf appearance was studied in nine species with different porosity patterns. Cylindrical stem cores and twigs were collected from early spring through late summer from deciduous (Quercus serrata, Liquidambar styraciflua, and Acanthopanax sciadophylloides), and evergreen (Castanopsis cuspidata; Cinnamomum camphora, Ilex pedunculosa, Symplocos prunifolia, Quercus glauca and Quercus myrsinifolia) species in a temperate forest. The first-formed twig vessels lignified at the time of leaf appearance or before in all species. The timing of stem vessel lignification in relation to leaf appearance in semi-ringporous deciduous species was overlapping with that of ring-porous deciduous species and diffuse-porous deciduous species. Evergreen species showed a great variation in the timing of stem vessel lignification, relative to leaf flushing. The main conclusions are that 1) Vessel lignification occurs much earlier in twigs than in trunks of the same trees, with hardly any overlap between the two; 2) Deciduous trees do not differ much from evergreen species, but there is a weak tendency for evergreen species to have later vessel differentiation than deciduous species; 3) The timing of vessel formation shows little relation with porosity patterns and overlaps between diffuse-porous and ring-porous species. This suggests a much greater intergradation of timing of vessel formation in species of different porosity pattern in evergreen and deciduous species than recognized in the literature. [ABSTRACT FROM AUTHOR]

We develop a new synthetic aperture radar (SAR) algorithm based on physical models for the detection of a man-made target (MMT) embedded in strong interferences (trunks of a forest). These physical models for the MMT and the interferences are integrated in low-rank subspaces and are based on scattering and polarimetric properties. Several images, called subspace SAR images, can be generated and combined considering these subspace models. We then propose a new approach for target detection and interference reduction based on the combination of SAR subspace images. We show that our SAR algorithm outperforms the classical SAR imagery algorithm on both simulated data and real data in the context of foliage penetration detection. [ABSTRACT FROM PUBLISHER]

Highlights: [•] Extensive field measurements of wind-induced deciduous broadleaved tree part response. [•] At least four vibration modes localized on all sampled tree parts (24 branches and trunk). [•] Wind excitation primarily occurs in other frequency ranges than tree part response. [•] Wind-induced tree response is a combination of forced and self-excited vibration. [Copyright &y& Elsevier]

Trunks of large trees play an important role in whole-plant water balance but technical difficulties have limited most hydraulic research to small stems, leaves, and roots. To investigate the dynamics of water-related processes in tree trunks, such as winter embolism refilling, xylem hydraulic vulnerability, and water storage, volumetric water content (VWC) in the main stem was monitored continuously using frequency domain moisture sensors in adult Betula papyrifera trees from early spring through the beginning of winter. An air injection technique was developed to estimate hydraulic vulnerability of the trunk xylem. Trunk VWC increased in early spring and again in autumn, concurrently with root pressure during both seasons. Diurnal fluctuations and a gradual decrease in trunk VWC through the growing season were observed, which, in combination with VWC increase after significant rainfall events and depletion during periods of high water demand, indicate the importance of stem water storage in both short- and long-term water balance. Comparisons between the trunk air injection results and conventional branch hydraulic vulnerability curves showed no evidence of ‘vulnerability segmentation’ between the main stem and small branches in B. papyrifera. Measurements of VWC following air injection, together with evidence from air injection and xylem dye perfusion, indicate that embolized vessels can be refilled by active root pressure but not in the absence of root pressure. The precise, continuous, and non-destructive measurement of wood water content using frequency domain sensors provides an ideal way to probe many hydraulic processes in large tree trunks that are otherwise difficult to investigate. [ABSTRACT FROM AUTHOR]

We investigated post-photosynthetic fractionation and carbon transfer mechanisms of different plant functional types growing under the same climatic conditions in North-eastern China. The variations in δC of trunk and branches were compared with leaf δC at different canopy heights of Pinus koraiensis (evergreen coniferous species), Larix gmelinii (deciduous coniferous species) and Quercus mongolica (deciduous broad-leaved species). Results showed that δC of leaves increased (became more enriched) with increasing canopy height for both coniferous species ( P. koraiensis, L. gmelinii) but not for Q. mongolica (a deciduous broad-leaved species). δC of both trunk and branches also increased with sampling height for the evergreen conifer P. koraiensis but did not significantly vary for either of the deciduous species ( L. gmelinii or Q. mongolica), except a significant increase in branch δC for L. gmelinii. Similarly, δC of trunk and branches were strongly correlated with leaf δC only in the evergreen conifer, P. koraiensis. C was consistently more enriched in trunk, branches, and roots compared to leaves in all three species. Our findings suggest that, even under the same climatic conditions, different plant functional types may exhibit different carbon transfer mechanisms. This is contrary to the previous hypothesis that different carbon transfer mechanisms operate in forests of different climatic zones, especially in tropical and temperate forests. Particularly, the differences occur predominantly between evergreen and deciduous trees rather than between coniferous and broad-leaved trees. The significant difference in δC between leaves and wood tissues confirms a previous post-photosynthetic isotope fractionation in temperate forests. [ABSTRACT FROM AUTHOR]

The article focuses on the Coccothrinax torrida, a new palm that was discovered in Southeastern Cuba in 2006 and is considered as one of the smallest species in the group in terms of trunk and leaf size. It says that Coccothrinax grows from 8 to 14 m tall on the hot dry coast of Southeastern Cuba. Furthermore, its trunks are gray and thin while its leaves are small, semi-orbicular and flat. It also mentions that its inflorescences measure 90-109 cm from base to tip.

Four alternative airborne laser scanning (ALS) canopy penetration variables were compared for their suitability for mapping of gap fraction, leaf area index and disturbances in a Scots pine forest. The variables were based on either echo counting or intensity, and on either first or first and last echoes. ALS data and field-measured gap fraction and effective leaf area index (LAIe) were gathered before and after a severe insect defoliation by pine sawflies. LAIe is a commonly used form of leaf area index that is mathematically derived from gap fraction, and includes the areas of foliage, branches and trunks, and which is not corrected for the clumping of foliage. The ALS penetration variables were almost equally strongly related to field-measured gap fraction and LAIe. The estimated slopes in the LAIe models varied from 0.94 to 2.71, and had coefficient of determination R2 values of 0.92-0.94. They were strongly correlated to each other (R2 values of 0.95-0.98) and agreed fairly well for temporal changes of LAIe during the summer and the insect defoliation (R2 values of 0.82-0.95). Counting of first and last echoes produced penetration rates close to the gap fraction, and this penetration variable was able to penetrate tree crowns. Ground-only echoes represented mostly between-tree gaps, and canopy-first-ground-last pulses represented mostly within-canopy gaps. However, the penetration variables based on first and last echoes suffered from the problem that a second echo might be impaired both in low and in tall canopies. In low canopies, two adjacent echoes from the same pulse would be too close in time to be separated by the sensor, while in tall canopies the pulse might apparently be fragmented down through the canopy. The intensity-based penetration variables needed to be supplemented with reflectance values, or at least the ratio between reflectance of the canopy and the ground, and this ratio was estimated from the data. The study demonstrated that one might be able to distinguish between disturbance types, e.g. between defoliation and cutting, by comparing alternative ALS penetration variables. Insect defoliation was dominated by an increase in within-canopy gaps and, correspondingly, the fraction of partly penetrating canopy-first-ground-last pulses. Tree removals from cutting were dominated by increases in between-tree gaps and the corresponding fraction of ground-only pulses. [ABSTRACT FROM AUTHOR]

The article offers information on the study concerning the efficacy of systemic insecticides on Quadrastichus erythrinae (gall wasp) in Wiliwili trees. There is little information regarding the control of gall wasp in wiliwili trees. Several systemic insecticides including abamactin, dinotefuran and imidacloprid were applied on the trees through trunk injections and soil drenches. After one year of treatment, imidacloprid remained detectable in the trees. It has been found that imidacloprid is the most effective insecticide against gall wasp among the three insecticides that were tested. The concentration level of imidacloprid in the leaves for good wasp control has been found out to 4 milligram per kilogram of leaves or higher.

Seventy trees from seven stands 50-650 years old were selected for this investigation of crown structural development in Pseudotsuga menziesii. All branches, limbs, and trunks were nondestructively measured for size, structure, and location while climbing the trees with ropes. These data were used to generate a computer model of each tree's crown that was error-checked trigonometrically. Leaves, bark, cambium, and wood were quantified by using limited destructive sampling to develop predictive equations that were applied to the complete inventory of structures in each tree's crown. Summations of these values yielded whole-tree estimates of several structural variables. A second set of equations was then developed to predict these whole-tree parameters from simple, ground-based measurements. Principal components analysis of 24 tree-level variables revealed two orthogonal dimensions of structure that accounted for 71.3% and 12.4% of total variation in the 70 trees. The first dimension represented a gradient of overall tree size and structural complexity that was positively correlated with tree age (R2 = 0.89). The second dimension represented a gradient of incremental growth potential that was positively correlated with measured growth of main trunks at breast height during the five-year period after trees were mapped (R2 = 0.39). The strongest determinant of incremental growth potential was the ratio of a tree's total cambium surface area to projected leaf area. A tree's incremental growth potential may thus be unrelated to either size or structural complexity and depend instead on factors related to whole-tree carbon balance (e.g., how much the tree invests in fighting and feeding fungi). Our intensive analyses of Pseudotsuga menziesii and extensive observations of other species were used to develop a conceptual model of crown development in tall conifers. Trees respond to disturbances by growth of replacement structures whose form depends on disturbance intensity and age. Young trees rebuild damaged crowns through epicormic shoot production on original branches, whereas older trees also recover by producing new, epicormic branches. Damage to main trunks and top dieback stimulate production of reiterated trunks. Repeated damage leads to multiple hierarchical levels of trunk reiteration as well as to limb formation and increasing tree individuality. [ABSTRACT FROM AUTHOR]

The article presents information on Tahina, a new palm genus from Madagascar. The area where this palm was found is a very remote part of north-western Madagascar and is very difficult to access by land. The palm has a big trunk to 18 meters tall with huge fan leaves up to 5 meters in diameter which makes it the biggest fan palm in Madagascar.

This study describes various symptoms associated with boron deficiency, one of the most common and widespread of all nutrient deficiencies in palms. The hook leaf symptom is best described as an acute zigzag near the tip of palm leaflets. Epinasty and trunk bending was the first clue that the loss of geotropism in palms was caused by boron deficiency. It is inferred that the lethal yellowing disease of C. nucifera is also characterized by necrosis of palm inflorescence and premature fruit drop.

We investigated changes in sapling growth and morphology of Thujopsis dolabrata var. hondai (hiba) for 7 years after release from suppressed lighting by selection cutting. We examined changes in aboveground biomass, elongation of stems and lateral branches, and annual diameter increment at the stem base. Vertical distributions of leaves per branch and per individual were also measured for morphological analysis. Under the suppressed condition before cutting, the crown consisted of orthotropic lateral branches, elongating up to the top of the stem or farther, and no branch was aborted. This crown type with large crown depth and concavity of the upper part had a bowl-like appearance. After the selection cutting, relative light intensity on the saplings increased from 4% to 26%. The increment enhanced aboveground biomass and stem elongation 7 years after the cutting. Diameter growth at the stem base was particularly accelerated 2 years after the cutting. While crown shape transformation of the saplings was not conspicuous at 7 years after the cutting, some released saplings showed a superior stem elongation ratio to that of the lateral branches. Thus, the upper part of the crown of these saplings changed from a bowl-like shape to a convex shape like that of a dome. Our study suggested that suppressed hiba saplings with the unique bowl-shaped crown enhanced their growth rates rapidly in response to improved light conditions, but required much more than 7 years for the full process of crown transformation for us to identify future trees in this stand. [ABSTRACT FROM AUTHOR]

Fruit concealed by several plant parts are often overlooked during harvest in okra (Abelmoschus esculentus (L.) Moench), causing significant reductions in marketable yield. Effects of plant traits contributing to marketable fruit being missed during harvest were tested in 15 okra cultivars having different plant architectures. Significant correlations between the percentage of overlooked fruit (POF) and several traits were found. There were significant correlations between POF and leaf area, numbers of lateral branches, plant height, number of nodes/ plant and internode length. Correlations between POF and plant height and internode length were negative. Fruit diameter, length, and weight; fruit weight/plant and fruit number/plant; petiole length; and stem diameter were not related to POF. The calculated bias and the coefficient of determination revealed that leaf area accounted for 62% of the variability observed for POF among cultivars; while internode length accounted for only 9% of variability. These plant traits should be considered in evaluation of cultivars for commercial production and in developing of breeding lines in okra. [ABSTRACT FROM PUBLISHER]

This essay presents the author's views about maple trees. The author says that the hang of the branches of maple trees is casual, occasional, and disorganized. He says that in his neighborhood, the maples were common, shading the front terraces, the sidewalks, the yards, and the back alleys. They offered a complex shadow, often solid, heavy, and dark on a hot summer afternoon. He says that many of the smaller branches of the trees have a tubular, rubbery look, rather like wires or cables. He says that a few of the main branches reach upward in a dignified way, but others fan out and away from the pattern and at the same time exhibit a tendency toward reaching across or down.

Leaf-specific conductivities (LSCs - hydraulic conductivity per dry weight of supplied leaves). Huber values (transverse sapwood area per dry weight of supplied leaves). specific conductivity (hydraulic conductivity per transverse sapwood area) and tracheid diameters were measured throughout the trunk and crown of 20-year-old trees of Abies balsamea (L. ) Mill. Measured specific conductivity was proportional to the radius to the fourth power of tracheids. LSCs, which indicate the relative water availability to different plant parts, are much higher in the trunk than in first order branches, and lowest in second order branches. The structural basis for this "hydraulic hierarchy" lies both in Huber values and in tracheid diameters. For similar diameter stem segments, there was no statistically significant difference for trunks versus branches in specific conductivity. However, in old parts of the tree, trunks are wider than supported branches and producer wider tracheids resulting in greater specific conductivities than in branches. In vigorous trees with strong apical control. Huber values were 12.0 times greater in the trunk than in similar diameter branch segments. In slow-growing trees with weak apical control, Huber values were 2.2 times greater in the trunk versus similar branch segments. [ABSTRACT FROM AUTHOR]

This paper discusses about the distribution of fluoride in polluted poplars and detection of fluoride accumulation in roots. In poplars polluted by fluoride, high concentrations of fluoride were detected in the lower part of the trunk, mainly in the cortical zone, and in the roots. This indicates that there is a basipetal translocation of fluoride from the leaves towards storage organs such as roots. This translocation of fluoride appears to be largely subordinate to the translocation of calcium.

This article presents a study regarding the biological flora of the British Isles. Hymenophyllum tumbrigense plant is a mat-forming bryophyte-like perennial, growing flattened against inclined or vertical rocks or tree trunks, with numerous overlapping, deeply pinnatisect leaves arising from very slender, much-branched interlaced rhizomes bearing tufts of adventitious roots at the nodes. The leaves are bright pale green when young. The plant is native and locally abundant on rocks in the west and north of Great Britain.

Features the Firefall freeman maple tree. Description of its trunk and leaves; Propagation; Availability.

The article looks into the effect of water stress and girdling on intra-annual δ13C of tree-ring. A model is used, which is based on leaf discrimination during photosynthesis. One goal of the researchers is to examine the link between leaf and ring, in terms of the δ13C signal. Moreover, they will investigate the impact of the constraints on the ring growth, the intra-annual pattern of ring δ13C and the trunk respiration.

The article presents a report of the research examining water potential measurements in trees. In the research, it was observed that water potentials of the small terminal twigs measured with the pressure chamber are lower than those of the trunk and branches. The water potential of the twigs and branches increase when the transpiration rate is reduced. Data obtained from the implanted stem psychrometers agree with data obtained from the pressure chamber and laboratory psychrometer after allowance is made for the gradient through the trees. It cites that leaf-water potential determinations do not give higher values than twig-water potential determinations with the pressure chamber.

This article presents information on a palm-like growth that flourished in a tropical environment in the middle Devonian Period, about 380 million years ago. Only fragments were previously known of the tree, called Pseudosporochnus. But in the 2004 Summer, staff from the New York State Museum in Albany came across a 3-meter-long specimen in a gravel quarry near Conesville, New York, the first time the foliage has been found attached to the trunk. It is well preserved with a crown made up of frond-like branches. Although no roots are in evidence, it gives the first clear impression of what this tree looked like, says William Stein of the State University at Binghamton, New York, who is studying the fossil. The fossil was described at the North American Paleontology Conference in Halifax, Nova Scotia, by New York state paleontologist Ed Landing.